This article describes how colouration of an object can arise due to interference of the light waves being reflected from the object.
Periodically arranged structures which act as point sources are one means of creating the condition that at certain angles only one specific wavelength will interfere constructively. The wavelengths that interfere constructively determine the colour of the object.
Examples of colouration in beetles by interference due to periodic structures is given.

How can alternating layers in a beetle's shell give the beetle brilliant colour?

This article explains how to derive the conditions for constructive interference for thin-film interference and finds the thicknesses of alternating layers of melanin and protein to give constructive interference at 635 nm.

How far away can a cheetah be from a gazelle and still be guaranteed to catch it?

This example combines both constant acceleration and uniform motion to determine the maximum distance that a gazelle can be away from a cheetah for the cheetah to have a chance of catching the gazelle.